What happens if you just stop paying?

Does anyone have any experience of quitting a timeshare? Just up and stop paying any more annual fees? I own at Sheraton's Vistana Resort near Disney World, and I cannot sell or give my timeshare away.( I've tried, many times, to give it away.) I don't want it, don't need it, and they don't care. It's all paid for. They are hounding me now every month, adding late fees, lockout charges.